Doxycycline and lymecycline are both tetracycline antibiotics, and NICE recommends either alongside a topical treatment for moderate to severe acne. They reduce inflammation as well as bacterial load, which is why they work for acne rather than merely for infection.
Choosing between them is usually about practicalities rather than potency.
Dosing and How You Take Them
Doxycycline
- Commonly 100mg once daily for acne
- Must be taken with plenty of water, sitting or standing upright, and not immediately before lying down — it can cause oesophageal irritation and ulceration if it lodges on the way down
- Absorption is reduced by dairy, antacids and iron or calcium supplements
Lymecycline
- Commonly 408mg once daily for acne
- Generally better tolerated on the stomach and less fussy about food
- Fewer administration rules, which for a months-long course matters more than it sounds
Sun Sensitivity
This is the most practically significant difference. Doxycycline causes marked photosensitivity — sunburn at exposures that would normally be harmless. In a UK summer, and especially on holiday, this catches people out repeatedly.
Lymecycline causes it too, but less commonly and usually less severely. If your course spans summer or you work outdoors, this alone may decide it.
Either way: high-factor sunscreen, and take it seriously rather than as a general precaution.
Side Effects
Shared across both: nausea, stomach upset, diarrhoea, headache and thrush. Doxycycline is more associated with stomach irritation and photosensitivity; lymecycline is usually the gentler of the two on the gut.
Both, rarely, are associated with raised intracranial pressure — persistent severe headache with visual disturbance needs urgent medical attention.
Who Cannot Take Either
- Pregnant or breastfeeding women
- Children under 12, because of effects on developing teeth and bones
- Anyone with a known tetracycline allergy
Cost
Both are generic and inexpensive as medicines. On a private prescription the difference between them is usually small, and the larger variable is what the supplying pharmacy charges for the consultation and prescription — which is exactly the kind of difference worth comparing rather than assuming.
Supply availability moves around for both, and a pharmacy that is out of one will often supply the other.
Which to Choose
- Sun exposure is a factor — summer course, outdoor job, holiday planned — lean towards lymecycline
- Sensitive stomach — lean towards lymecycline
- You already tolerate doxycycline from a previous course — no reason to change
- Cost is decisive — compare the total price at the supplying pharmacy, not the drug
The Part That Matters More Than the Choice
Whichever you take, take it with a topical treatment — benzoyl peroxide or a retinoid — because that improves results and reduces resistance. Agree a review point rather than an open-ended course. And have a maintenance plan for when the antibiotic stops, or the acne will simply return and you will be back where you started with more antibiotic exposure behind you.