COVID19 Supplements: Do Vitamin C, Vitamin D or Tongkat Ali help the immune system against COVID19?

Last Updated: 30th December 2023

COVID-19 cases are rising again in 2023 is projected to record higher cases into 2024. Whilst COVID-19 vaccination is not compulsory in most countries, dealing with symptoms related to COVID-19 such as dry cough, fever, loss of appetite and taste, headaches and sore throat continue to affect our lives.

According to health experts, most of the COVID-19 related cases are due to weak immune systems, and those who are immunocompromised are likely to catch COVID-19. On this note, many believe that taking supplements may protect them from COVID-19 viruses and various coronaviruses.

But do supplements such as Vitamin C, Vitamin D and Zinc work against COVID-19?

We shall deep-dive into which supplements work against COVID-19 and should you even consider buying herbal supplements such as Tongkat Ali, Ashwagandha and other herbs.


The US National Institute of Health (NIH) recently evaluated the effectiveness of dietary supplements against COVID-19. According to NIH, Vitamin C, Vitamin D and Zinc may not work to prevent or treat COVID-19. However, many other herbal supplements have been used in the recovery of COVID-19 patients by strengthening their immune systems, which underpinned the principle of protecting the body from virus attacks.

Users are warned against buying dietary supplements such as Zinc or magnesium for the treatment or prevention of COVID-19 viruses as it may worsen the condition.

Here is the summary of dietary supplements that may not work against COVID-19 as reported by the National Institute of Health (NIH).

Dietary Supplements Guide for COVID-19

Vitamin C

According to NIH, there is lack of evidence for the COVID-19 Treatment Guidelines Panel (the Panel) to recommend either for or against the use of vitamin C for the treatment of COVID-19 in nonhospitalized patients. The Panel further advised users or patients against using Vitamin C for the treatment of COVID-19. Alternative herbal supplements such as Tongkat Ali (Eurycoma Longifolia) may provide a significant boost of immune cells compared to Vitamin C.


Vitamin D

There is insufficient evidence for the Panel to recommend either for or against the use of vitamin D for the prevention or treatment of COVID-19. Do not buy Vitamin D if you have COVID-19 and save your money for other immune-boosting supplements such as Tongkat Ali (Eurycoma Longifolia)



The Panel recommends against using zinc supplementation above the recommended dietary allowance (i.e., zinc 11 mg daily for men, zinc 8 mg daily for nonpregnant women) for the prevention of COVID-19.


Note: For a full list of supplements that are under review by NIH, kindly refer to the NIH website before buying any dietary supplements for COVID-19.

NIH Fact Sheet for Health Professionals: Dietary Supplements for COVID19

Does Tongkat Ali help boost your immune system?

The short answer is yes. Our research revealed that Tongkat Ali exhibits strong properties that strengthen your immune cells. A randomized placebo-controlled clinical study by a group of Japanese scientists showed an increase in immune-related cells in test participants, i.e CD4+, Naive T-cell and T-cells; after consuming Tongkat Ali extract at 200mg daily for four weeks. The result also showed an increase of immunological grade by 12.9%, which suggests strong evidence that Tongkat Ali helps boost the immune system which may further prevent the proliferation of the COVID-19 virus in the human body.

Here is a quick summary of the clinical study.


Research Objective:
  • To find out if Tongkat Ali can improve the immune system in the human body.
  • To measure immune-related cells and other parameters before and after consuming Tongkat Ali.
  • To observe other adverse effects, or side-effects associated with Tongkat Ali consumption.
Dosage :
  • 200mg of Physta® standardized Tongkat Ali extract daily
Test Subjects:
  • 83 males – with randomized placebo groups
Duration :
  • Four weeks
Results :
  • Naïve T-Cell: + 28%
  • CD4+ T-Cell: + 12%
  • T-Cell count: + 6.5%
  • Scoring of Immunological Vigor (SIV): +4.8%
  • Immunological Grade: +12.9%
Research Conducted By

Does Tongkat Ali work against COVID-19?

A recent in-vitro study published in the Journal of Natural Products showed that quassinoids in Tongkat Ali (Eurycoma Longifolia) contain anti-coronavirus properties against two types of COVID-19 viruses, i.e HCoV-OC43 and SARS-CoV-2.

Another review 2021 study lists Tongkat Ali as one of the herbs including gymnanthemum amygdalina, azadirachta indica and nigella sativa, that may have a potentially beneficial role in COVID-19 prevention and treatment.

The study further suggests the use of Tongkat Ali as a potential treatment against COVID-19, and Tongkat Ali may be used as a dietary supplement if you plan to strengthen your immune system as evidenced in other clinical studies.

Can I take Tongkat Ali if I have COVID-19?

Taking Tongkat Ali or any other dietary supplements should be exercised with caution. If you have mild symptoms due to COVID-19 or if you are recovering from COVID-19, you may take Tongkat Ali or other herbal supplements in low dosages.

It is not recommended to take Tongkat Ali if you are hospitalized due to COVID-19 or if you experience chronic COVID-19 symptoms. It is best to consult your healthcare professionals before consuming Tongkat Ali or any dietary supplements.

COVID19 and our immune system

When our body is exposed to virus attacks such as COVID-19, our immune system acts as the first line of defense. Therefore, choosing the right dietary supplements may work to strengthen your immune system and this will reduce the likelihood of catching flu, cold or even COVID-19 viruses.

However, our immune system and cells both decline as we age and dietary supplements may play a role in restoring the overall hormonal balance to strengthen our immune system against virus attacks. 

Therefore, for dietary supplements to work, the ingredients must contain properties that contribute to the immune parameters (eg: increasing T-cells and other immune cells), or anti-COVID19 properties. Users are advised that taking anti-bacterial and anti-fungal supplements, or even probiotics may not work against COVID19. 

Immune-related studies on COVID19
  • Researchers at the Peter Doherty Institute for Infection and Immunity in Australia found that the recovery of a patient diagnosed with COVIDI19 was due to an unexpectedly strong immune response. The 47-year-old woman in Melbourne who made a remarkable recovery from COVID19 saw all symptoms related to COVID19 had disappeared by day 13.
  • A study led by researcher Chen Dong of the Institute for Immunology and the School of Medicine at Tsinghua University in Beijing showed high levels of antibodies in patients who recovered from COVID19 . The findings have been accepted for publication in the Journal of Immunity.

These anecdotal events suggest the importance of strengthening our immune system from flue, virus attacks and potentially COVID-19. In addition, multiple immunological studies have shown the importance of T-cells in fighting viruses, more than the antibodies themselves.

In our view, the significance of our immune system, what we eat (dietary requirements) and supplementation may act as a preventive measure from possible recurrence from COVID-19 attacks.

"T cells play a more important role than antibodies during natural infection"

Tongkat Ali is one of the natural remedies alongside panax ginseng that you can take to prevent COVID-19 by increasing your T-cells and other immune cells. Whilst Tongkat Ali should not be viewed as an effective treatment or prevention, more studies should be undertaken to ascertain the efficacy against various strains of COVID-19.

Users who opt for Tongkat Ali supplements may also gain other advantages from its antifungal, anti-microbial and antibiotic properties against yeast infection / bacterial infection. 

Does Tongkat Ali Increase T-cells or immune cells?

A research study by a group of scientists in Japan found strong evidence that Tongkat Ali (Eurycoma Longifolia) can potentially improve our immune system. The placebo controlled randomized study showed higher CD4+ T-cells, Lymphocytes, Naive T-cells, and other T-cells found in the group of test subjects who consumed Tongkat Ali vs placebo group. 

The published paper from this study can be found here with a new patent filing which can be found here.

Japan is known for its investment in research and technology on herbs and other traditional medicines for centuries.

The deep-dive study of Tongkat Ali was conducted by a group of independent experts from Japan and Malaysia:

In order to gain a better understand of this mechanism of action works, lets take a view of our immune system.

Our immune system

Our immune system is essentially the natural defense mechanism that protects us from viruses, bacteria and other “attacks” from other “bad cells”.

On the other hand, an antibody is a protein component of the immune system that circulates in the blood, recognizes foreign substances like bacteria and viruses, and neutralizes them. This forms a part of the immune system.

The immune system is a complex system made up of multiple organs and vessel systems, including a sophisticated network of individual cells and proteins.

Here are essential parts of the immune system:

  • White Blood Cells (WBC)
  • Antibodies
  • Complement system
  • Lymphatic system
  • Spleen
  • Bone Marrow
  • Thymus

In fact, when you first become infected with a virus, your body will launch a standard innate immune defense. And this innate immune response is behind many of the symptoms you experience when you are sick.

Contained in those organs and network are microscopic cells that are not visible to our naked eye. The cells that are responsible to protect our immune system are called CD4+ and T-cells.

Let’s explain the functions of these cells.

Key facts on T-Cells

T-cells are a subset of White Blood Cells (WBC) that play a crucial role in our body’s immune system. T-cells are also commonly known as immune cells, which can be activated due to supplement intake such as Tongkat Ali or from other form of interventions.

T cells are found in almost every organ and tissue in our body including lymphoid tissue, mucosal and barrier sites, exocrine organs, fat, and even in the brain and central nervous system.

T-cells are one of the key immune-related cells that are activated due to quassinoids and alkaloids found in Tongkat Ali.

Types of T-cells

There 5 common types of T-cells with a different set of functions:

  • Cytotoxic T-cells
  • Helper T-cells
  • Regulatory T-cells
  • Natural killer T-cells
  • Memory T-cells


The most important T-cells are the cytotoxic T-cells. Its primary role is to find and attack bacteria, viruses, and cancer cells.

Cytotoxic T cells regulate our immune responses – by releasing perforin and granzymes, and attack infected or cancerous cells as illustrated below:

Cytotoxic T-cells (or commonly known as T-cells) respond by attacking the “bad” or “weak cells”.

Key facts on CD4+ T-Cells

  1. CD4 is a type of protein found on immune cells like T-cells, macrophages, and monocytes. So in short, T-cells contain CD4 – or more commonly described as CD4+ T-cells.
  2. CD4 cell count gives you a measure of the condition of your immune system, i.e which includes your body’s natural defence system against pathogens, infections and illnesses.
  3. For healthy adults, the amount of CD4 varies according to age and CD4 count can typically around 500 to 1500 cells per cubic millimeter of blood (mL).
  4. CD4 count is a common measurement used by doctors in diagnosing HIV / AIDS patients. If a patient’s CD4 count falls below 200, then your life expectancy reduces drastically. Here is a chart taken from a study by the University of Bristol UK, which was published here

How do you measure immune system?

If you are taking supplements, several tests can be performed to measure the state of your immune system which can act as a prevention performance indicator against COVID-19.

In the previous study conducted by Japanese scientists to validate the effectiveness of Tongkat Ali in boosting the immune system, each test subject was tested and the following measurements were recorded:

  • Scoring of Immunological Vigor (SIV)
  • Total T cells (CD3+ cells)
  • CD4+ T cells
  • CD8+ T cells
  • CD8+CD28+ T cells
  • naïve T cells (CD4+CD45+ cells)
  • memory T cells (CD45+CDRO+ cells)
  • B cells (CD20+ cells),
  • natural killer (NK) cells (CD16+CD56+ cells);
  • ratios of CD4+/CD8+ T cells and naïve/memory T cells
  • T cell proliferative activity
  • T cell proliferative index (TCPI)
  • immunological age
  • T lymphocyte age

How effective is Tongkat Ali on the immune system?

Tongkat Ali is a hormone-inducing adaptogen plant that requires days or even weeks to work optimally. To gain the full effect on the immune system, the clinical trial showed statistically significant results after four weeks.

At week 4, the SIV and immunological grade were significantly higher in the Tongkat Ali group compared to the Placebo group (p-value <0.05). Meanwhile, the number of total, naïve, and CD4 T-cell counts was higher in the Tongkat Ali administered group compared to the placebo group.

Between-group comparisons showed the most significant increases in the following:

  • Lymphocytes (P < 0.05)
  • Total T cells (P < 0.05)
  • CD4+ T cells (P < 0.01)
  • Naïve T cells (P < 0.05).

Research Paper on Tongkat Ali

Immunomodulation in Middle-Aged Humans Via the Ingestion of Physta® Tongkat Ali Eurycoma Longifolia  – A Randomized, Double-Blind, Placebo-Controlled, Parallel Study

Author: Annie George, Naoko Suzuki, Azreena Abas, Kiminori Mohri, Masanori Utsuyama, Katsuiku Hirokawa and Tsuyoshi Takara 

Publisher: Phytotherapy Research Journal 2016

Download the full research paper from Phytotherapy Research for free.

Results of immune system parameters

The increase of CD4 T-cells found in the test subjects means consuming Tongkat Ali can improve our chances to strengthen our immune system. Remember, a higher number of the CD4 T-cells in our body correlates to a better immune system.

At the same time, there were no severe adverse events reported by test subjects throughout the 4 week period.

Absolute values for each immunological parameters from the research study (taken from Week 0 to week 4) were summarized in the figures below.

Here is the result of consuming Tongkat Ali and its effect on the human immune system based on immune system parameters (n=83 test subjects)

Naive T-Cell Count


Week 0 - (Baseline)
Week 4 - (After)

CD4+ T-Cell Count


Week 0 - (Baseline)
Week 4 - (After)

Scoring of Immunological Vigor (SIV)


Week 0 - (Baseline)
Week 4 - (After)

Immunological Grade


Week 0 - (Baseline)
Week 4 - (After)

T-Cell Count


Week 0 - (Baseline)
Week 4 - (After)



Week 0 - (Baseline)
Week 4 - (After)

Tongkat Ali properties that helps your immune system

Tongkat Ali root contains quassinoids and alkaloids, two major compounds that are heavily investigated on its efficacy against COVID-19. In fact, not only it help boost your immune system, but the quassinoids in Tongkat Ali contain anti-coronavirus properties coupled with anti-bacterial properties that reduce the spread of viruses or bacteria infection in your body.

In 2011, the Journal of Current Medicinal Chemistry stated that over 150 quassinoids from Tongkat Ali have been found. Quassinoids display a wide range of inhibitory effects, including anti-inflammatory, anti-viral, anti-malarial and anti-proliferative effects on various tumor cell types.

The paper titled “Quassinoids: From Traditional Drugs to New Cancer Therapeutics” showed possible applications of quassinoids and quassinoid derivatives in modern medicine.

FAQ: User Guide

Can I consume Tongkat Ali if I have immune-related medical conditions or diseases?

It is not recommended to consume Tongkat Ali to improve your immune system if you are diagnosed with any of the following immune-related conditions, diseases or complications.

  • Multiple Sclerosis (MS)
  • G6PD deficiency
  • Systemic lupus erythematosus (SLE)
  • Psoriasis/psoriatic arthritis
  • Addison’s disease
  • Other chronic immune system disorders

Whilst there are no reported studies on the side-effects from patients diagnosed with the above medical conditions consuming Tongkat Ali, it is recommended for you to consult your nearest doctor, or stop consuming Tongkat Ali if there is a severe effect on your health.

For more information on daily dosage and maximum allowable limit, kindly refer to our dosage guide.

Parting Thoughts

Most dietary supplements such as Vitamin C, Vitamin D, Vitamin E, Zinc and Magnesium may not work effectively against COVID-19 while herbal supplements such as Tongkat Ali and Panax Ginseng may offer an alternative solution by strengthening your immune system, which may reduce the likelihood of catching COVID-19. 

However, despite Tongkat Ali’s antiCOVID-19, antioxidant, anti-fungal, anti-microbial and immune-boosting properties, more research is required to confirm the effectiveness of Tongkat Ali against COVID-19.

Users are advised to consult a healthcare professional or their nearest doctor before buying dietary supplements to protect themselves against COVID-19. 

Naressa Khan contributes regularly on AKARALI. As a writer and journalist, Naressa is all about creating, deconstructing, and reassembling meanings through words. With this approach always in mind, she eagerly explores the nuances in life via the aspects of lifestyle, culture, travel, health, and wellness.

Disclaimer: Content published in this article is not intended to promote any brands nor to provide any form of recommendations to purchase or consume medication, drugs or herbal supplement brands directly or indirectly. By reading this, the sole responsibility and decision lies on the reader to perform their own assessment and / or to arrive at an informed decision based on publicly available information. By reading the content published on this website means you are aware on the risks involved in purchasing any of the products or brands mentioned in this article. We highly recommend you and the readers to consult your nearest doctor before making any purchase from this website or any other websites or social platforms after reading this article.

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3 Responses

  1. I have used this tongkat ali for only a few weeks. Started by taking it in the am. Didn’t notice any physical or mental changes, but since my insomnia has been a runaway train for months. About a week ago, I started taking it after dinner. It’s better than all the drugs and crap I have tried over 30 years. I am sleeping hard. At nearly 60 years old, I do get up to pee nightly, and it’s been a chore. I am so sleepy and it’s lights out when I get back to bed. I wake up with the alarm and get up with no hangover. Feeling better than ever! I even started up my exercise routine before breakfast, slowly of course as it’s been five years. But I actually feel like trying. If this does nothing else for me, feeling rested each day is enough to keep using tongkat ali.

    1. Hi John. Thanks for sharing your feedback and experience. There is a small percentage of our customers that shared the same experience. This is quite normal as your body regulates itself to the effect of Tongkat Ali. Soon the warm tingly sensation will dissappear after few days.

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