Description
Insulin Glargine (brand name Lantus) is a long-acting insulin analogue designed as a basal insulin. Two changes are built into the molecule compared to human insulin: at position A21 asparagine is replaced by glycine, and two additional arginine residues are attached at the end of the B chain. These modifications shift the isoelectric point of the molecule into the neutral range. In practice that means: in the acidic solution inside the pen, glargine sits clearly dissolved, while in the neutral environment of subcutaneous tissue it immediately precipitates as a fine microprecipitate. From that depot the active substance redissolves slowly and evenly. At the insulin receptor itself the substance acts like endogenous insulin: glucose uptake into muscle and fat cells, suppression of hepatic glucose production, inhibition of lipolysis. In tissue, glargine is rapidly processed at the end of the B chain, so what mainly circulates in blood is the active metabolite M1.
Pharmacokinetically, this depot principle is the decisive difference. Lepore et al. (2000) compared glargine, NPH insulin, ultralente and continuous pump infusion under an isoglycemic 24-hour clamp in 20 people with type 1 diabetes. Onset of action for glargine came later than for the comparators at 1.5 hours, while end of action came markedly later at 22 hours versus 14 hours for NPH. Above all, glargine was the only subcutaneously administered preparation with no peak effect: NPH and ultralente showed a pronounced maximum after roughly 4.5 and 10 hours respectively followed by waning, while glargine delivered a flat profile close to that of pump infusion. Hence the term peakless. The concentration is 100 IU per ml, that is U100.
The clinical evidence base is extensive. Ratner et al. (2000) treated 534 adults with type 1 diabetes for up to 28 weeks and found lower fasting values under glargine alongside fewer symptomatic hypoglycemic events (39.9 versus 49.2 percent) and fewer nocturnal events (18.2 versus 27.1 percent) than under NPH. Riddle et al. (2003) reached practically identical HbA1c values with both basal insulins in the Treat-to-Target trial across 756 people with type 2 diabetes, but roughly a quarter more participants reached the target without documented nocturnal hypoglycemia. Heise et al. (2004) put this in context: under clamp conditions the variability of glargine’s effect was lower than that of NPH but greater than that of insulin detemir. Peakless therefore means more even, not predictable.
The largest data base comes from the ORIGIN trial (NEJM 2012). 12,537 people with cardiovascular risk factors and dysglycemia were randomized for a median of 6.2 years to either glargine targeting a fasting glucose value or to standard care. The result was neutral: no difference in cardiovascular events, no difference in cancers. What clearly did differ were the side effects. Severe hypoglycemia occurred more than three times as often under glargine (1.00 versus 0.31 events per 100 person-years), and median weight rose by 1.6 kg while it fell by 0.5 kg in the comparison group. ORIGIN is therefore simultaneously the best evidence for the long-term safety of the substance and the best evidence that hypoglycemia is not a marginal phenomenon but the price of the main effect.
In a research context, insulin glargine belongs to the substances with the narrowest safety margin in the entire catalog, and the long duration of action shifts the danger profile compared to rapid-acting insulins rather than shrinking it. An excessive dose of a rapid-acting insulin is cleared after a few hours. A glargine depot keeps working for roughly a full day afterwards, and there is no way to retrieve, neutralize or accelerate it once injected. A single dose of sugar does not cover that time window. On top of that come two documented confusion classes: mixing up basal and mealtime insulin, and mixing up different concentrations. U300 preparations contain three times the amount of active substance in the same volume as U100. Anyone working without diabetes and without blood glucose measurement additionally has no objective feedback whatsoever about where their glucose level currently sits.
You can order Insulin Glargine as a clear solution for subcutaneous injection at a concentration of 100 IU per ml, in the 3ml size containing 300 IU per unit.
This information is for research and educational purposes only. No medical advice.
Risks & Safety
Insulin Glargine is a clinically approved basal insulin with a very well characterized effect profile and a multi-year outcome trial behind it. The risk does not come from unknown side effects but from the main effect itself: the substance lowers blood glucose reliably and dose-proportionally, it does not stop doing so once a safe value is reached, and it does so across roughly 24 hours. That is why this product sits in risk tier 3.
Documented in clinical studies and in the drug safety literature:
- Hypoglycemia across a 24-hour window: the central, dose-limiting risk. Early signs are tremor, sweating, palpitations, intense hunger and nervousness, followed by impaired concentration, slurred speech, confusion, and aggressive or slowed behavior. With a further drop come seizure, unconsciousness and death. The cognitive impairment sets in precisely when independent corrective action would be required. In ORIGIN, severe hypoglycemia occurred more than three times as often under glargine as under standard care.
- No taking it back after injection: the microprecipitate in subcutaneous tissue releases the active substance across the whole day. It cannot be removed, neutralized or shortened. An excessive dose has to be sat out in full, under continuous observation and with repeated carbohydrate intake. A single dose of sugar brings brief improvement and does not cover the time window.
- Nocturnal hypoglycemia: clinical schemes typically give basal insulins in the evening, which puts a relevant part of the action window into sleep. Hypoglycemia during sleep can go unnoticed because the warning symptoms are slept through. Ratner et al. and Riddle et al. therefore recorded nocturnal hypoglycemia as a separate endpoint.
- Never alone, never without measurement: without a blood glucose meter there is no objective feedback on the current value, and subjective impression is unreliable while glucose is falling. Without a second person present who can recognize an emerging loss of consciousness and call for help, the only remaining safeguard against incapacitation is missing. Fast-acting carbohydrates (glucose tablets, juice, sugared drinks) must be within reach before administration, not somewhere in a cupboard.
- Potassium shift: insulin transports potassium from the extracellular space into cells. Serum potassium falls as a result, without any change in total body stores. Pronounced hypokalemia can trigger cardiac arrhythmias, and this risk is independent of blood glucose: carbohydrates alone do not correct it.
- Confusion of preparation and concentration: mixing up basal and mealtime insulin is a documented medication error class, because both are clear solutions in visually similar pens. Concentration is equally critical: U300 preparations contain three times the amount of active substance per unit of volume as U100. Insulin is dosed in International Units, not in ml or mg, and a syringe not calibrated for U-100 is a documented cause of severe overdose.
- Do not mix, do not give intravenously: the delayed release depends on the acidic pH of the solution. If glargine is mixed with other insulins in one syringe or diluted, the precipitation behavior changes and with it the entire time profile, in an unpredictable way. Administered intravenously, the depot effect disappears completely.
- Alcohol and physical exertion: alcohol suppresses hepatic gluconeogenesis and therefore disables exactly the mechanism the body uses to catch a hypoglycemic episode on its own. Muscular work additionally increases insulin-independent glucose uptake. Both amplify and prolong the glucose-lowering effect considerably and to a poorly predictable degree.
- Further documented effects: weight gain (median 1.6 kg in ORIGIN), injection site reactions, lipohypertrophy with repeated injection into the same region making absorption unpredictable, sodium and water retention with edema, and rarely allergic reactions.
This classification does not replace medical advice. Risk and responsibility for any actual use lie entirely with the buyer. If severe hypoglycemia is suspected, particularly with confusion or clouded consciousness, calling emergency services is the only correct response.
Studies
- Pharmacokinetics and pharmacodynamics of subcutaneous injection of long-acting human insulin analog glargine, NPH insulin, and ultralente human insulin and continuous subcutaneous infusion of insulin lispro - Diabetes 2000, Lepore et al: 24-hour clamp in 20 type 1 diabetics, onset at 1.5 hours, end of action at 22 hours versus 14 hours for NPH, no peak effect.
- Less hypoglycemia with insulin glargine in intensive insulin therapy for type 1 diabetes - Diabetes Care 2000, Ratner et al: 534 adults for up to 28 weeks, lower fasting values with 39.9 versus 49.2 percent symptomatic and 18.2 versus 27.1 percent nocturnal hypoglycemic events.
- The treat-to-target trial: randomized addition of glargine or human NPH insulin to oral therapy of type 2 diabetic patients - Diabetes Care 2003, Riddle et al: 756 participants over 24 weeks, same HbA1c reduction as NPH but roughly a quarter more target attainment without documented nocturnal hypoglycemia.
- Lower within-subject variability of insulin detemir in comparison to NPH insulin and insulin glargine in people with type 1 diabetes - Diabetes 2004, Heise et al: clamp comparison of variability, glargine more even than NPH but more variable than insulin detemir.
- Basal insulin and cardiovascular and other outcomes in dysglycemia (ORIGIN) - NEJM 2012, ORIGIN Trial Investigators: 12,537 participants over a median of 6.2 years, neutral for cardiovascular and cancer outcomes, but more than triple the rate of severe hypoglycemia plus weight gain.
