Understanding the Link: Can Levothyroxine Cause Acne?

October 14, 2025 •

4 min read

While the active ingredient in levothyroxine is not a known direct cause of acne vulgaris, many people who start thyroid replacement therapy report new or worsening skin issues. This raises a critical question: is there a connection between the medication and breakouts, and if so, what is the underlying mechanism?

Quick Summary

Levothyroxine does not typically cause acne, but indirect factors tied to its use can. Causes include dosage-related hormonal fluctuations, allergic reactions to inactive ingredients, or unresolved symptoms from underlying hypothyroidism affecting gut health and skin oil production.

Key Points

Indirect Link: Levothyroxine's active ingredient is not known to cause acne, but indirect factors are often the cause.
Dosage Matters: Incorrect levothyroxine dosage can disrupt the hormonal balance that impacts sebum production, contributing to acne.
Allergic vs. Acne: Rashes and hives caused by an allergic reaction to excipients in the medication are distinct from acne and may require switching brands.
Gut Health Connection: Hypothyroidism can affect gut health, which in turn causes systemic inflammation that can appear as skin problems like acne.
Integrated Approach: Managing acne while on levothyroxine involves optimizing dosage, addressing gut health, evaluating skincare products, and managing stress.

Is there a direct link between levothyroxine and acne?

Medical experts generally agree that the active ingredient in levothyroxine, a synthetic thyroid hormone, does not directly cause acne. Acne vulgaris is a common inflammatory skin condition where hair follicles become clogged with oil, bacteria, and dead skin cells. The standard medical understanding does not list levothyroxine among the medications known to trigger acne.

However, this doesn't mean your skin problems are unrelated to your thyroid treatment. The connection is often more nuanced and indirect, involving factors like medication side effects, changes in hormone levels, and even ingredients in different brand formulations. Distinguishing between a medication-related issue and an allergic reaction is crucial. Allergic reactions to levothyroxine or its inactive ingredients (excipients) can cause skin rashes, hives, and itching, which may sometimes be mistaken for acne, but these reactions are typically different from the characteristic pimples and cysts of acne vulgaris.

Indirect causes linking levothyroxine to acne breakouts

Several indirect mechanisms can explain why an individual taking levothyroxine might experience acne:

1. Dosage imbalances

Achieving the right dosage of levothyroxine is a delicate balance. If the dose is too high, it can induce symptoms of hyperthyroidism, such as excessive sweating and heat sensitivity. Increased sweating and oiliness can lead to clogged pores and breakouts. Conversely, if the dose is too low and the underlying hypothyroidism is not adequately managed, it can perpetuate skin problems that are common with low thyroid function. Regular monitoring of TSH levels by your doctor is essential to ensure proper dosage.

2. Hormonal fluctuations

Thyroid hormones are interconnected with other endocrine functions, including sex hormones like estrogen and progesterone. For individuals with hypothyroidism, this can lead to an estrogen dominance, which is known to cause acne breakouts, particularly around the jawline. Starting levothyroxine can cause significant hormonal shifts as the body rebalances, and this transition period can trigger temporary skin flare-ups.

3. Gut health disruptions

Patients with hypothyroidism or autoimmune thyroid conditions like Hashimoto's often experience gastrointestinal issues, including small intestinal bacterial overgrowth (SIBO) and intestinal permeability. A disrupted gut microbiome can lead to systemic inflammation that manifests as skin issues, including acne. Addressing gut health through diet and supplements can be an important part of managing skin symptoms.

4. Hypersensitivity to inactive ingredients

In rare cases, a skin reaction may be caused not by the active levothyroxine itself but by a specific inactive ingredient (excipient) in a particular brand. Many brands of levothyroxine contain different fillers, dyes, and binders. For example, a patient may react to lactose in one brand but tolerate a lactose-free or liquid formulation. It is worth discussing alternative brands with your doctor if you suspect an excipient allergy.

How to manage acne while taking levothyroxine

If you're experiencing acne while on levothyroxine, consider the following steps:

Optimize Your Dosage: Work closely with your endocrinologist to ensure your TSH levels are stable and within the optimal range. Hormonal fluctuations during dosage adjustments can trigger breakouts.
Address Gut Health: Consider a high-quality probiotic and a diet rich in whole foods to support a healthy gut microbiome. Avoiding inflammatory foods may also help.
Evaluate Skincare Products: Hypothyroidism can cause dry, sensitive skin, which may react poorly to harsh or pore-clogging products. Switch to gentle, non-comedogenic cleansers and moisturizers.
Manage Stress: High stress levels increase cortisol, which can exacerbate acne and affect thyroid function. Practices like yoga, meditation, and adequate sleep can help.
Explore Skincare Treatments: Dermatologists can recommend topical treatments like benzoyl peroxide or retinoids (like tretinoin), which can be safe for patients with thyroid conditions but should be discussed with your doctor.
Consider a Brand Switch: If you suspect a reaction to inactive ingredients, discuss switching to a different brand or formulation, such as a liquid version without common allergens, with your healthcare provider.

Comparison of potential acne causes on levothyroxine


Cause	Mechanism	Symptoms	Resolution	Diagnosis
Dosage Imbalance	Hormonal fluctuations (too high or too low dose) affect sebum production and overall skin health.	Persistent or new acne, often accompanied by other hyper- or hypothyroid symptoms.	Optimizing levothyroxine dosage with a doctor.	Regular TSH testing by a healthcare provider.
Allergic Reaction	Hypersensitivity to the active or inactive ingredients (excipients) in the medication.	Hives, rashes, itching, or swelling, not typical acne lesions.	Discontinuing the medication or switching to a different formulation/brand.	Skin patch testing or drug provocation test.
Underlying Condition	Hypothyroidism or Hashimoto's impacts gut health, estrogen/progesterone balance, and skin regeneration.	Chronic or cystic acne, often along with GI issues or other hypothyroid symptoms.	Address underlying hormonal or gut health issues, in addition to acne treatment.	Evaluation of overall health by a doctor and specialist.

Conclusion

While the direct link between levothyroxine and acne is weak, the indirect connections are significant and worth investigating. The complexity arises from the interplay of hormones, gut health, and individual sensitivities. Experiencing acne after starting levothyroxine is not uncommon and points to the need for a comprehensive approach to treatment, rather than simply discontinuing the medication. By working with your healthcare team to ensure proper dosage, addressing potential gut issues, and tailoring your skincare routine, you can effectively manage both your thyroid condition and your skin health. Always communicate any persistent side effects with your doctor to find the best solution for you.

Frequently Asked Questions

It is not a direct or typical side effect, but it is not unusual to experience skin changes. This is often due to hormonal shifts as your body adjusts to the medication and its new metabolic balance, rather than the medication itself.

Yes, an incorrect dose can be an indirect cause. A dose that is too low may not resolve the underlying hormonal issues of hypothyroidism, while a dose that is too high can cause symptoms of hyperthyroidism like excessive sweating that can lead to breakouts.

An allergic reaction typically presents as hives, itching, or redness and is a hypersensitivity response. Acne from hormonal imbalances involves clogged pores leading to pimples, blackheads, and cysts.

Yes, in rare cases, hypersensitivity to inactive ingredients (excipients) in a specific brand can cause skin reactions. If you suspect this, consult your doctor about switching brands or using a liquid formulation.

Start by confirming your dosage is correct with your doctor. Address potential root causes like gut health and stress. Use gentle, non-comedogenic skincare products and discuss topical treatments like retinoids or benzoyl peroxide with a dermatologist.

Yes, hypothyroidism can cause acne due to a slower metabolic rate affecting skin cell turnover, hormonal imbalances (such as estrogen dominance), and links to gut health issues. The goal of levothyroxine treatment is to correct these underlying issues.

For many, stabilizing thyroid levels with levothyroxine helps resolve skin issues related to hormonal imbalance and metabolism. However, if other factors like gut health or stress are at play, additional management may be needed.