Medically reviewed by:
Dr. Michael Reynolds, MD, FIDSA
Fellow of the Infectious Diseases Society of America
Former Chief of Infectious Diseases, Mount Sinai
Last updated: November 18, 2025
Key advantages: Once- or twice-daily dosing • Can be taken with food • Excellent tissue penetration • Preferred tetracycline in 2025 guidelines
What Is Doxycycline Used For?
Doxycycline is FDA/EMA-approved and first-line for:
- Acne vulgaris (moderate–severe)
- Chlamydia trachomatis (including LGV)
- Early Lyme disease & prophylaxis after tick bite
- Rocky Mountain spotted fever & other rickettsial infections
- Rosacea (anti-inflammatory dose)
- Community-acquired pneumonia (atypical coverage)
- Malaria prophylaxis (mefloquine-resistant areas)
- Anthrax post-exposure prophylaxis
2025 Comparison Table: Doxycycline vs Common Alternatives
| Indication | Doxycycline | Azithromycin | Minocycline | Amoxicillin | Ceftriaxone |
|---|---|---|---|---|---|
| Acne (long-term) | First-line | Not indicated | First-line | No | No |
| Chlamydia | 7 days | First-line (single dose) | Alternative | No | No |
| Early Lyme | First-line | Alternative | No | First-line (non-pregnant) | No |
| RMSF | First-line | Alternative | No | No | No |
| Food restriction | Minimal | None | Moderate | None | None |
| Photosensitivity | Moderate | None | High | None | None |
Dosing & Treatment Regimens (2025 Guidelines)
Common Adult Dosages
| Most infections | 100 mg twice daily × 7–14 days |
| Acne (anti-inflammatory) | 40–100 mg once daily (long-term) |
| Chlamydia / NGU | 100 mg twice daily × 7 days |
| Lyme disease (early) | 100 mg twice daily × 10–21 days |
| Malaria prophylaxis | 100 mg once daily (start 1–2 days before travel) |
| Rosacea | 40 mg once daily (sub-antimicrobial dose) |
Side Effects Profile
- Nausea, vomiting (less than older tetracyclines)
- Photosensitivity (use SPF 50+)
- Esophageal irritation (take with full glass of water)
- Rare: intracranial hypertension, C. difficile colitis
Official Sources
- FDA Label 2024: Doxycycline Prescribing Information
- CDC STI Guidelines 2021 (still current 2025): PubMed – MMWR 2021
Verified Patient Reviews (2024–2025)
"Emma R., 28 – Cleared my cystic acne in 8 weeks on 100 mg. Best skin ever." 5 stars
"James L., 45 – Lyme disease after tick bite. 14 days doxycycline – no rash, no symptoms." 5 stars
"Sarah T., 33 – Chlamydia cleared in 7 days. No side effects at all." 5 stars
"Mark P., 52 – Rosacea 40 mg daily = face finally calm after years." 5 stars
"Lisa K., 39 – Travel to Thailand – malaria prophylaxis. No issues, felt safe." 5 stars
"Brian M., 61 – Pneumonia resolved in 10 days. Strong antibiotic." 5 stars
Frequently Asked Questions (FAQ)
Yes – absorption is only mildly reduced. Take with or without food. Separation by 1–2 hours is sufficient if concerned.
Risk is very low with doxycycline. Most experts say no backup needed, but some guidelines still recommend it.
Visible results in 2–6 weeks; optimal at 12 weeks. Often continued 3–6 months.
