Nicotine and smoking act on tendon and bone repair through the blood supply and the cells that build new tissue, which is why recovery can lag even when rehabilitation is done well. In a rat Achilles tendon model, nicotine-exposed tendons contained significantly fewer vascular structures than controls and were measurably weaker at 42 days.1 In human cells, it was whole cigarette smoke extract rather than nicotine alone that impaired wound closure and bone-forming capacity — a distinction worth understanding before you plan a procedure around it.2
Key takeaways
- In a rat Achilles tendon injury model, nicotine exposure reduced vascular structures at the repair site.1
- In the same model, healed tendon at 42 days carried 44.7% less maximum load and 35.0% less stiffness than saline controls.1
- In cultured human mesenchymal stromal cells, cigarette smoke extract — not nicotine alone — produced dose-dependent delay in wound closure and reduced calcium deposition.2
- Among 126 patients followed at least two years after arthroscopic rotator cuff repair, the 18 smokers improved less on one shoulder score but not on pain or the other outcome measure.3
- None of this data tells you what will happen to your specific repair. It tells you which variables are worth removing before the healing window opens.
What nicotine did to tendon in the animal model
The clearest tendon-specific evidence comes from a controlled rat study in which 60 adult male Sprague-Dawley rats received either saline or nicotine at 61 ng/mL through subcutaneously implanted osmotic pumps, starting three months before injury and continuing throughout.1 Animals were evaluated at 21 and 42 days after a full-thickness Achilles injury.
Blood supply at the repair site
Histology showed significantly fewer vascular structures in the nicotine-exposed tendons than in controls, and ultrasound analysis showed slower vascular inflow.1 Tendon repair depends on that inflow to deliver cells, oxygen, and signaling factors, so a thinner vascular bed is a plausible mechanism rather than an incidental finding.
Mechanical strength at 42 days
By 42 days, the nicotine group’s healed tendons carried 44.7% less maximum load and were 35.0% less stiff than controls, with a smaller cross-sectional area and decreased stress relaxation.1 Tissue that looks healed on a timeline is not necessarily tissue that performs under load, and this is the study that separates those two things.
What cigarette smoke did to human bone-forming cells — and what nicotine alone did not
A 2024 laboratory study exposed human mesenchymal stromal cells, the precursors that support bone formation, to nicotine-concentration-standardized cigarette smoke extract and to nicotine alone.2 The two exposures did not behave the same way, and the difference matters for how this topic is usually described.
Wound closure and cell survival
Cigarette smoke extract produced a dose-dependent delay in wound closure, and at high concentrations of 3,200 to 4,500 ng/mL the cells shrank, detached, and died.2 Nicotine alone did not produce a comparable dose-dependent impairment of wound closure in these cells.
Bone-forming capacity
Smoke extract also caused a dose-dependent decrease in calcium deposition during osteogenic differentiation, while nicotine at equivalent concentrations had negligible effect on calcium deposition or alkaline phosphatase activity.2 In this cell model, the components of smoke other than nicotine carried the bone-side burden.
What the human surgical data show
In a cohort of 126 patients followed for a minimum of two years after arthroscopic rotator cuff repair, 18 patients — 14% of the cohort — were smokers.3 Both groups improved to a clinically meaningful degree, but the smokers gained less on the ASES shoulder score, improving 19.4 points against 35.2 points in non-smokers.
The same report notes that smokers arrived with higher baseline pain, more comorbidity, and worse baseline shoulder scores, and that the difference did not reach across to the pain scale or the other functional measure used.3 This is a real signal in a modest cohort, not a verdict.
How this changes planning for orthobiologic care
Every orthobiologic we use is autologous — it works by asking your own repair biology to respond. When the vascular bed at the repair site is thinner and the surrounding cell environment is under chemical stress, you are asking the same procedure to work against more resistance.
Timing around the healing window
The animal data placed its measurements at 21 and 42 days after injury, which is a reminder that the first weeks are biologically active rather than dormant.1 Where exposure reduction is possible, it is most worth the effort across that window, and we build the schedule around it. We describe how that sequencing works in our approach to conservative-first planning.
Where PRP, BMAC, and Lipogems fit
Nicotine status does not by itself select one biologic over another; the tissue target and the clinical indication do that. It does change what we tell you to expect and how closely we monitor the response. The categories we work with are set out under orthobiologic services.
When conservative care has been exhausted
Regen.MD is conservative-first, and Dr. Gurpreet Singh Padda, MD, MBA, MHP is a surgeon. When conservative measures have genuinely been exhausted, surgery remains available and is discussed openly rather than treated as a failure of the plan. For the shoulder specifically, that decision point is covered on our shoulder surgery alternatives page.
Find out what is actually driving your pain
Regen.MD begins with a physician-led Clinical Evaluation — a review of your history, imaging, and metabolic data, and a written terrain roadmap. Evaluation is contingent upon review of your data.
Questions? Call (314) 295-3000 or text (314) 886-5902.
Frequently asked questions
Does nicotine by itself harm healing, or is it the rest of the smoke?
Both questions have answers, and they are not the same answer. In the rat Achilles model, nicotine alone was enough to reduce vascular structures and mechanical strength in healing tendon. In the human bone-marrow stromal cell study, whole cigarette smoke extract impaired wound closure and bone-forming capacity while nicotine alone at matched concentrations did not.
The honest summary is that nicotine is not neutral for tendon, and the non-nicotine components of smoke carry their own separate burden for bone-forming cells. More background reading is collected in the Regen.MD library.
Will quitting before a procedure change my result?
No study cited here randomized patients to quitting before an orthobiologic injection, so we cannot promise you a specific gain. What the evidence supports is narrower and still useful: nicotine exposure was associated with fewer vascular structures and weaker healed tendon in the animal model, and smokers in the rotator cuff repair cohort improved less on one of three outcome measures.
Reducing exposure removes a variable that works against the repair environment rather than for it. How we sequence that against the rest of a plan is described in our conditions and care pathway pages.
If I still use nicotine, will you refuse to treat me?
No. Nicotine use is a factor we account for in planning and in the expectations we set with you, not a gate we use to turn people away. It changes the conversation about timing, about how we monitor response, and about how much of the outcome we attribute to the injection itself.
Systemic and metabolic contributors are handled in the same visit, including topics covered under physician-directed peptide and longevity medicine, which we discuss as clinical subjects rather than products.
Who reviews my imaging and builds the plan?
The Clinical Evaluation is physician-led. Dr. Gurpreet Singh Padda, MD, MBA, MHP reviews your history, imaging, and metabolic data, and the resulting roadmap is written rather than delivered verbally and forgotten.
His background and scope of practice are set out on the Dr. Padda page.
Sources
- Cheema AN, Newton JB, Boorman-Padgett JF, Weiss SN, Nuss CA, Gittings DJ, Farber DC, Soslowsky LJ. “Nicotine Impairs Intra-Substance Tendon Healing After Full Thickness Injury in a Rat Model.” Journal of Orthopaedic Research, 2018. https://pmc.ncbi.nlm.nih.gov/articles/PMC6411046/
- Heikkinen J, Tanner T, Bergmann U, Palosaari S, Lehenkari P. “Cigarette smoke and nicotine effect on human mesenchymal stromal cell wound healing and osteogenic differentiation capacity.” Tobacco Induced Diseases, 2024;22. https://www.tobaccoinduceddiseases.org/Cigarette-smoke-and-nicotine-effect-on-human-mesenchymal-stromal-cell-wound-healing,185281,0,2.html
- Naimark M, Robbins CB, Gagnier JJ, Landfair G, Carpenter J, Bedi A, Miller BS. “Impact of smoking on patient outcomes after arthroscopic rotator cuff repair.” BMJ Open Sport & Exercise Medicine, 2018;4(1):e000416. https://pmc.ncbi.nlm.nih.gov/articles/PMC6267295/