Shellac: What It Is and Why It’s in Your Pills

You've probably seen "shellac" listed on a medicine leaflet and wondered what it is. Quick answer: it’s a natural resin used as a glaze or coating on tablets, capsules and even candies. Pharmacies use it to protect pills from moisture, mask tastes, and sometimes to control how a drug dissolves in your gut.

Where shellac comes from and what it does

Shellac is made from resin secreted by the lac insect. Processed and purified, it becomes a clear, shiny coating called pharmaceutical glaze or E904 in food labeling. In meds, shellac serves a few concrete jobs: it keeps moisture out so pills last longer, gives a smooth finish that makes swallowing easier, and can act as a simple enteric-like layer that slows release in the stomach. It’s cheap, stable, and has been used in industry for decades.

Safety, allergies, and common concerns

For most people shellac is safe — regulators allow it in foods and drugs. But a small number of people report allergic reactions, usually contact dermatitis or irritation. If you get itching, rash, or mouth irritation after taking coated pills, mention shellac to your doctor or pharmacist. Also, vegans and strict vegetarians often avoid shellac because it’s insect-derived. If that’s important to you, look for "shellac-free" labels or ask your pharmacist for alternatives.

Shellac doesn’t interact with medicines the way active drugs do, so it rarely affects how a medication works. Still, if a tablet’s coating causes stomach upset or swallowing issues, your healthcare provider can recommend a different formulation (liquid, capsule, or uncoated tablet).

Want to know if your medicine contains shellac? Check the package insert under "excipients" or "inactive ingredients." Shellac may be listed as "pharmaceutical glaze," "shellac," "lac resin," or "E904." If the leaflet is unclear, call the manufacturer or ask the pharmacist — they can confirm ingredients quickly.

Need shellac-free options? Practical steps: ask your pharmacist for an uncoated tablet or an alternative brand, look for oral liquids or dissolvable forms, or see whether a compounding pharmacy can prepare a shellac-free version. For many common drugs there’s usually at least one alternative formulation available.

Short, practical checklist:

• Read the excipient list for "shellac," "pharmaceutical glaze," or "E904."

• Tell your pharmacist if you have allergies or avoid animal-derived ingredients.

• Ask about different formulations (liquid, uncoated, or capsule).

If you suspect an allergy after taking a coated pill, stop the product and contact a healthcare professional. For diet or ethical concerns, pharmacists are used to helping find suitable shellac-free alternatives. Small changes like switching brands or form can solve the issue without messing with your treatment plan.