Why Too Much Vitamin D, Zinc, B12, or Biotin Could Be Making Your Acne Worse

As a Nutritionist, I often get asked which supplements can help improve skin. And while deficiencies in certain vitamins can certainly play a role in acne, the other side of the story is rarely talked about: taking too much of certain supplements can actually trigger breakouts.

I’m not someone who’s naturally acne-prone, but I’ve experienced phases of breakouts before — including a stretch of more aggressive forehead acne. From both my own experience and what I’ve seen in practice, supplementation is an area many people overlook when trying to understand why their skin is reacting.

In this post, I’ll break down the most common supplements that can contribute to acne when taken in excess, why they affect the skin, and how to approach them more strategically.

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Vitamin B12, Vitamin D, and Zinc: The Hormonal Trio

Individually, each of these nutrients supports critical processes in the body. But when taken in high doses, they share one important effect: all three can increase testosterone levels.

This surge in testosterone can drive hormonal acne, which often shows up in the classic “mustache and goatee” pattern—around the jawline, upper lip, and chin.

The tricky part is that many people don’t realize how easily these nutrients stack. Multivitamins, energy supplements, protein bars, and immune-boosting drinks often contain overlapping amounts of B12, vitamin D, and zinc. While one product on its own might not be an issue, combining several throughout the day can quietly push intake into excess territory.

Vitamin B12.

Vitamin B12 is essential for energy and nervous system function. But in high doses, it can alter the way skin bacteria behave and increase testosterone levels—both of which can contribute to acne.

Research has shown that excess B12 can change the activity of Cutibacterium acnes, causing it to release more inflammatory compounds that drive breakouts. Many multivitamins, B-complex supplements, and energy drinks contain thousands of percent of the daily recommended value. This is why B12-related breakouts often appear around the jawline and cheeks, mimicking hormonal acne.

Vitamin D.

Vitamin D is often called the “sunshine vitamin,” but it acts more like a hormone in the body. In the right amount, it supports bone health, immunity, and hormone balance. But when taken in excess, it can raise testosterone and alter DHT (dihydrotestosterone) activity, both of which are linked to acne. Because vitamin D is fat-soluble, it builds up over time—especially if taken without cofactors.

Unlike other nutrients, vitamin D can be more difficult to obtain consistently from food alone. That’s why I do recommend supplementing with a vitamin D3 + K2 formula under the instruction of a healthcare provider. K2 ensures vitamin D is metabolized properly and directed into the bones instead of soft tissues.

Magnesium also plays a supportive role here, since it’s involved in hundreds of enzymatic processes in the body and helps regulate how vitamin D is used. For many people, focusing on magnesium-rich foods—like dark leafy greens, nuts, seeds, and cacao—can be a helpful complement to supplementation.

And just as important: lifestyle practices like safe sun exposure, morning light to regulate circadian rhythm, and stress management all support the body’s ability to use vitamin D effectively.

Biotin.

Biotin is popular for hair, skin, and nail health. But in excess, it drives hyper keratinization—excess keratin production in the skin that clogs pores and worsens acne. For someone already acne-prone, this can feel like pouring gasoline on a fire.

Rather than leaning heavily on biotin supplements, focus on whole food sources like salmon, egg yolks, almonds, and sweet potatoes. These provide biotin in balanced amounts, alongside other nutrients that work together synergistically. And since skin health depends on more than just biotin, it’s equally important to prioritize protein, healthy fats, and blood sugar stability—all of which support healthy skin barrier function and natural repair.

Zinc.

Zinc plays a key role in immunity, collagen production, and hormone balance, and at the right dose it can benefit acne. But when taken in excess, it can spike testosterone and deplete copper, an important mineral for energy, mood, and skin repair.

Zinc also plays a critical role in testosterone production and overall hormonal health—especially for men. But I don’t typically recommend taking a standalone zinc supplement without considering the bigger mineral picture. Too much isolated zinc can interfere with copper absorption, leading to imbalances.

That’s why I recommend prioritizing food sources like pumpkin seeds, oysters, and grass-fed beef, or even pumpkin seed oil for hormone support. If supplementation is needed, look for blends that combine zinc with cofactors like copper. And remember—sleep, stress, blood sugar regulation, and quality fats are just as important for testosterone and skin health as minerals.

The Bottom Line.

Acne is multifactorial—stress, diet, hormones, and skincare all play a role. But supplementation is often overlooked. Both deficiencies and excesses can contribute to breakouts, and the real issue usually comes from stacking: multivitamins, energy powders, protein bars, and immune drinks that together push nutrient levels far beyond what the skin can handle.

As a Nutritionist, my approach is simple:

• Prioritize whole foods over pills.

• Use supplements thoughtfully, not habitually.

• Pay attention to your body’s signals when adding something new.

Clear, healthy skin isn’t about mega doses—it’s about balance. Supporting your skin means finding the right levels, not chasing extremes.

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A Brand I Trust for Acne-Safe Skincare & Supplements

I also want to highlight one of my favorite brands, CLEARSTEM Skincare. Their ethos is rooted in education, transparency, and helping people truly understand the connection between what we put in (and on) our bodies and how it shows up on our skin. From their skincare line to their acne-safe supplement guidance, CLEARSTEM consistently emphasizes balance over extremes—an approach that aligns perfectly with my philosophy as a Nutritionist.

If you’d like to try them, you can use my code ASHLEYD for 20% off.

References

• Kang, D., Shi, B., Erfe, M. C., Craft, N., Li, H. (2015). Vitamin B12 modulates the transcriptome of the skin microbiota in acne pathogenesis. Science Translational Medicine, 7(293), 293ra103.

• Ozuguz, P., Dogruk Kacar, S., Ekiz, O., Takci, Z., Balta, I., & Kalkan, G. (2014). Evaluation of serum vitamins A and E and zinc levels according to acne severity. Cutan Ocul Toxicol, 33(2), 99–102.

• Mock, D. M. (2017). Biotin: From nutrition to therapeutics. Journal of Nutrition, 147(9), 1487–1492.

• Maqbool, S., Shah, H. U., & Nawaz, H. (2020). Role of zinc therapy in acne vulgaris: A review. Dermatologic Therapy, 33(6), e14148.

• Livingstone, C. (2015). Zinc: Physiology, deficiency, and parenteral nutrition. Nutrition in Clinical Practice, 30(3), 371–382.

• CLEARSTEM Skincare. (2018). Does Biotin Cause Acne?

• CLEARSTEM Skincare. (2020). Vitamin D and Acne: Why It’s Making You Break Out

• CLEARSTEM Skincare. (2023). Does Vitamin B12 Cause Acne?