Introduction
The honest answer is that you don't know, and neither does anyone reading this, because the question is answerable only by measurement.
Much of what substances do to a body is silent for years. Livers fail quietly. Hearts remodel without symptoms. Deficiencies accumulate and get mistaken for tiredness. By the time something announces itself, a great deal has usually already happened.
So this article is a map of where to look, and a list of what to ask for. It is general information, not a diagnosis, and it is not a substitute for a doctor who knows your history.
The Systems, Briefly
Liver. Alcohol's principal target. The progression runs fatty liver, to inflammation, to fibrosis, to cirrhosis. The early stages are largely reversible and produce almost no symptoms; cirrhosis is generally not reversible. Which stage you are at is knowable, and it changes everything about your prognosis.
Heart and vessels. Stimulants constrict blood vessels and stress the heart; chronic use is associated with cardiovascular damage. Alcohol affects blood pressure and rhythm. Erectile difficulty is a recognized early marker of vascular disease, because the arteries involved are narrower and show impairment first.
Brain. Structural changes are measurable and substantially recoverable with sustained abstinence, though not always completely. Cognitive symptoms in early recovery are usually temporary; persistent ones need investigating rather than accepting.
Lungs. Smoking anything damages them. Injecting introduces its own pulmonary risks.
Hormones. Opioids suppress the signalling axis that produces testosterone, a recognized and treatable condition. Alcohol disrupts hormones through several routes.
Nutrition. Frequently the most urgent and least examined. Alcohol both reduces thiamine absorption and increases the body's demand for it, and severe deficiency can cause permanent memory damage. B12, folate, magnesium, and zinc deficiencies are common and are routinely mistaken for depression or fatigue.
Teeth, skin, and bone. Visible, slow to recover, and often the changes people find hardest to look at.
Infection. Injecting carries risk of HIV, hepatitis B and C, abscesses, and endocarditis — infection of the heart valves.
What You Cannot Feel
This is the reason for the article.
Liver disease is famously asymptomatic until it is advanced. Hypertension has no sensation. Hepatitis C can sit for decades without a symptom and is now curable — but only if someone finds it.
Feeling fine is compatible with a great deal going wrong. Feeling terrible is compatible with nothing structural being wrong at all. Your subjective sense of your own health is nearly worthless as evidence, and this is true of everyone, not only of you.
Two Things That Are Emergencies
Most of this article is about slow, silent damage. Two things are not, and they get missed.
Withdrawal from alcohol or benzodiazepines can kill you. Stopping abruptly after sustained heavy use can cause seizures and delirium tremens. If either is part of your daily pattern, talk to a doctor before you reduce, not after something goes wrong.
Thiamine deficiency can cause permanent damage, quickly. Severe deficiency, most associated with chronic alcohol use, can produce Wernicke's encephalopathy — a medical emergency which, untreated, can progress to irreversible memory damage. Confusion, unsteadiness, or eye movement problems in a heavy drinker are not something to sleep off.
Neither of these waits for an appointment next month.
The Tests to Ask For
Go in with specifics. Vague worry produces vague reassurance.
Liver function tests, and ask what the numbers actually mean for your stage. Ask whether imaging or a fibrosis assessment is warranted.
Full blood count and metabolic panel.
Thiamine and B12, particularly if alcohol has been involved. Ask directly; it is not always routine.
Hepatitis B, hepatitis C, and HIV — if you have ever injected, or shared any equipment, or are unsure. Hepatitis C is curable. It is worth knowing.
Testosterone, if you have used opioids and have low libido, fatigue, or erectile difficulty.
Blood pressure, fasting lipids, fasting glucose — standard cardiovascular assessment, and specifically indicated if you have erectile difficulty.
An ECG, if stimulants have been involved.
Vaccination status for hepatitis A and B. Both are preventable. There is no vaccine for hepatitis C or HIV.
Tell Them the Truth, Including the Amount
The single thing that most improves the quality of the answer you get.
People universally underreport. Doctors know this and adjust, which means understating your intake produces an inaccurate assessment rather than a flattering one.
Yes, some clinicians handle this badly — a documented phenomenon in which physical symptoms get misattributed to substance use, delaying real diagnoses. That is a reason to find a better doctor, not a reason to conceal information that determines your treatment. A surgeon who doesn't know what you take can hurt you.
What Actually Reverses
Worth knowing which side of the line things fall on.
Substantially reversible with abstinence: fatty liver, hormonal suppression from opioids, most cognitive fog, blood pressure, nutritional deficiencies if caught, hepatitis C with treatment.
Partially reversible: fibrosis, some brain structure, cardiovascular damage.
Generally not reversible: cirrhosis, established organ damage, some nerve damage, dental damage, permanent memory damage from untreated thiamine deficiency.
The variable that most determines where you land is not which substance you used. It is how much longer the exposure continues.
The Bottom Line
You cannot know how this is affecting you by how you feel, because the things that kill people are silent until they suddenly aren't. Go to a doctor with a written list: liver function, thiamine and B12, hepatitis B and C and HIV if you have ever injected, testosterone if opioids were involved, cardiovascular screening if stimulants were. Tell them the real amount. Much of this is reversible if it is found in time, and the single largest factor in where you end up is how soon the exposure stops.